On a map, a closed shape defined by a connected sequence of x,y coordinate pairs, where the first and last coordinate pair are the same and all other pairs are unique.

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How to split polygons based on other polygons?

In ArcGIS, I have a layer of polygons (created from the Service Area function) and want to split each one of those based on another polygon layer (the boroughs of London). The purpose is that I want ...
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701 views

How to Smooth Polygons after converting DEM using Raster to Polygon?

I have a DEM SRTM that I classify using Spatial Analyst Tools > Reclass > Reclassify. The result is box shaped so I go to Layer Properties > Display and choose cubic convolution. The result is ...
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1answer
2k views

combine raster and polygon values in R

My question is similar to this one Get Raster Values from a Polygon Overlay in Opensource GIS Solutions but I think I need another step. I have a polygon layer of ecoregions which I brought into R ...
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2answers
681 views

Retrieve common paths of polylines ArcObjects

I have a polygon featureClass and a polyline featureClass. I now want to handle all geometries within the latter that are contained in the boundaries of polygon features, that means they shell simply ...
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1answer
149 views

Move shared vertices together

I should move some vertices of a polygon to fix the boundaries of a country, how can I do it while keeping the adjacent polygons still connected? Is there a way to anchor permanently overlapped ...
2
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1answer
202 views

Union of polygons doesn't work 100 % correctly

I'm using the function gUnaryUnion to merge polygons in R. In one particuliar case this doesn't work correctly - some of the old polygon contours are still visible: Can anybody help ?
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1answer
2k views

How to find the intersection point of polygon geometry and multilinestring geometry in postgis

I have a polygon geometry and multilinestring geometry. How do i find the intersection of both these geometries. Both the geometries are in same reference system. Does st_intersection gives me the ...
2
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1answer
903 views

Distance of points in polygon to nearest polygon edge

I have a polygon shapefile with about a dozen polygons (Area.shp). I have an equation that calculates a value for points (or small areas) as a function of distance to the edge of these polygons. I ...
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0answers
69 views

How to measure area of polygons generated from gps data in qgis? [duplicate]

Somebody classified my question as a duplicate. But applying the answer doesn't work for me. Here is what I did: - I made sure that my layer is in a projected coordinate system (UTM30N, WGS84) - I ...
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4answers
4k views

Percentage of polygon in one shapefile within polygon of another

I'm a newbie, apologies if this is obvious/has already been asked and answered but I couldn't find anything. I have two shapefiles: 1. an administrative boundary layer for a county in the UK known as ...
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0answers
82 views

Unwanted lines when cutting & merging polygons

I am using QGIS version 1.8.0. Sometimes when I cut or merge polygons I get unwanted lines left in them. On zooming in to them they do not appear to be slivers. Is there a way of getting rid of these ...
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0answers
283 views

Divide polygon evenly based on lines and intersection points

I have this purple polygon illustrated in the figure below. I would like to split the polygon so that each line segment (green) split the polygon evenly with the surrounding line segments. A line ...
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1answer
366 views

Sum of point attributes inside hexagons using QgiS UI

I'm very new to Qgis so I would very much appreciate any help you can give me. I have a point shapefile that corresponds to locations of animals captured. I've joined a table to this shapefile with ...
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1answer
83 views

How can I know the number of polygons in a selected area in QGIS

How can I know the number of polygons in a selected area in QGIS? Can I use the Select features tool? How can I use? Thank you
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1answer
228 views

Aggregating a raster to fit a polygon grid

I am working at the scale of 10 square km grid cells for the UK, and have a polygon layer of the Ordnance Survey 10k grid cells in ArcGIS. I have another layer of the human footprint index, also for ...
4
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1answer
2k views

How to add CSV data with no coordinates to a polygon layer in QGIS?

I would like to add attributes from an spss database (around 300 cases) to a polygon layer in QGIS. Both datasets have a column with unique IDs. I exported the spss data to a CSV file which does not ...
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1answer
105 views

Can this compilation and display of species frequency data be improved? QGIS 1.8.0

As a newbie on QGIS, I would like to find out if the way I put a species frequency map together could be improved upon. I had to map the presence or absence of 7 plant species surveyed in 30 2m x 2m ...
6
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1answer
2k views

Identify polygon overlaps within single shapefile

Using either QGIS (1.9) or ArcInfo (9.3.1) I'm trying to identify unique overlaps of prehistoric building footprints from an archaeological site recorded within a single polygon shapefile. While the ...
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4answers
201 views

How can I calculate different polygons by different attributes?

I'm doing my master thesis and want to calculate different polygons (in QGIS 1.8 for Mac) in four different columns which I defined by different attributes. i.e. some of the attributes in the first ...
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0answers
98 views

Tiles cover Polygon on zoom and move

i'm using OpenLayers.Geometry.Polygon.createRegularPolygon to generate some nice circles. After i draw them to the Map i'm Moving them and after some while they where hiding by some tiles. The circle ...
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0answers
148 views

How to create sector figure in ArcObject?

How to create sector in ArcObject 10.1? Now I draw one point, two lines, two arks. But I think it is not good. It is differents objects. I need one object. Well. Now I drawing: IElementCollection ...
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1answer
386 views

How to find and quantify duplicate vertices on a polygon/polyline in ArcGIS 10.0

I need to clean up topological errors in various shapefiles and databases. I did read that the Repair Geometry tool could clean duplicate vertices but how can I know the number of errors before and ...
5
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4answers
16k views

QGis: Merge intersecting polygons into one which are part of the same feature

I'm not a GIS professional so I hope I use the correct wording, at least I hope you understand my question. Let's say there are 5 polygons in the feature A. In the shape file there are more ...
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2answers
1k views

How do I find the average distance within a polygon to a point?

For my purposes, I can assume a homogeneous distribution of points within the polygon. What I want to find is the average distance from points within a polygon to a specified point. I don't know where ...
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2answers
789 views

Clip polygon and retain data

I have these two polygons: library(sp); library(rgeos); library(maptools) coords1 <- matrix(c(-1.841960, -1.823464, -1.838623, -1.841960, 55.663696, 55.659178, 55.650841, ...
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1answer
883 views

Reverse geocoding polygon co-ordinates?

I have a large dataset of polygons for property sections that I need to reverse geocode. It was recommended that I use a GIS like Quantam to do this however from my research I am not 100% sure if a ...
2
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1answer
256 views

Tools/Script to reshape automaticaly topologic edges within a given distance in ArcGis 10?

I have a footprint feature class and a land use cluster feature class. I am looking for a method/tool/script that would allow me: to reshape two edges into one (topologically) to decide at which ...
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2answers
716 views

Where to find the variables of QgsPolygon and QgsPolyline?

now I want to use QgsPolygon (and Qgspolyline,too) class in python I have a example by using QgsPoint but I don't know how to use in QgsPolygon following is my Qgspoint example feature = ...
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2answers
596 views

How to shift polygons by updating their details in R

I have two polygon shapefiles and I want to see to what extent the observed amount of overlap is due to chance. I'd like to randomly move the polygons in one shapefile to new locations, measure the ...
2
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1answer
1k views

How to perform a cascaded combine from python script in QGIS?

I'm working with a large dataset, and I need to be able to combine up to 400,000 polygons. I have been using the QgsGeometry::combine(QgsGeometry* geometry) function and simply looping over all ...
4
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2answers
1k views

How to average values in a point layer with respect to polygon layer in QGIS?

I am new to GIS and have the following problem: I have 2 layers: a point layer with a column that contains numbers (pollution index from specific measurement point) and a polygon layer with different ...
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1answer
3k views

How to write a point-in-polygon query for Postgis?

I'm trying to write a query in Postgis which will return all rows where a dynamically changing longitude/latitude point resides within the geometric polygon of that row (in the geom column). This is ...
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1answer
9k views

Joining polygons in R

I am wondering how to join spatial polygons using R code? I'm working with census data where certain areas change over time and I wish to join the polygons and the corresponding data and simply ...
7
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2answers
3k views

How do I get that polygon from Javascript ArcGIS API?

I would like to have a user draw a Polygon (or Line) onto a web map with the Javascript ArcGIS API drawing tools. For the life of me I can't figure out how to pull that polygon from the client and get ...
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4answers
323 views

Web service to see postgis polygons

Is there any website or web service where I throw a polygon postgis and he show me on the map this polygon. Example: I put this POLYGON((0 0, 1 0, 1 1, 0 1, 0 0)) and the service show me the ...
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1answer
210 views

QGIS create point data attribute as the name of the polygon it falls in

I'm working in QGIS with a point data set overlaying a farm with 140 fields. While I can analyse the points from each field individually, I would rather use an awk script to calculate statistics I ...
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3answers
339 views

Is there Shape Metrics Toolbox or equivalent for ArcGIS 10?

I need to compute the geometric properties (e.g. contiguity index, dispersion index etc.) of a series of polygons and I would like to use the Shape Metrics Toolbox. I am using ArcGis 10 and the ...
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1answer
171 views

How to paste pictures into data frame?

I have a polygon feature class and I want to trace (select with a polygon) a picture that is solely comprised of a couple of interlocking letters. In ArcMap when I would do this I would simply drag ...
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1answer
1k views

Creating Multi-Part Polygons that touch internally using ArcGIS for Desktop?

I have a set of parcels as illustrated in the image below. There are currently no multi-part features in dataset. What I would like to do is to merge (not the right word) all of the parcels with same ...
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2answers
2k views

How to convert self intersecting polygon to multipolygon?

Working with the union and polygonize methods in GDAL/OGR, I often end up with self intersecting polygons. The case is one polygon which essentially consists of two polygons: In the above example, ...
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1answer
189 views

Remove parts of line that fall within a polygon

I have a polygon and two lines. How can I remove the portion of each line that falls within the polygon? # polygon coords <- matrix(c(-1.798123, -1.793072, -1.805767, -1.804129, -1.798123, ...
3
votes
2answers
379 views

Detecting ring direction of a polygon using ArcPy

I am using ArcPy in ArcGIS 10.1 to process some geometry using the arcpy.da data access module. However I have run into a problem with complex Polygons that contain inner rings/holes. From the ...
2
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0answers
287 views

Commit Feature WPS Split process

I develop a WebGIS application with GeoServer (2.1.1) and GeoExt (with the last version of OL). Data (polygons features) are stored in a postgis DB. I've implemented editing tools that allow users to ...
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1answer
5k views

Control view of Multi polygon in Google map

We have multipolygon WKT. We have no issue to draw all of them in Google map. Below are the codes. The only issue is that we want only the first polygon to be visible but the rest to transparent. How ...
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1answer
83 views

For each polygon, return yes/no value if it intersects another layer

I have a polygon grid overlaying several other polygon vectors. I wish to visit each polygon in the grid and ask yes/no if each of these layers fall within the grid cell or not. I can do this easily ...
13
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2answers
3k views

How to speed up the plotting of polygons in R?

I want to plot the country borders of North America over a raster image depicting some variable and then overlay contours on top of the plot using R. I have been successful in doing this using base ...
2
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0answers
271 views

Divide polygon layer by point layer in QGIS?

I have two layers - one polygon layer that is a buffer of a road layer, and one point layer that shows certain locations along that road. What I want to do is to divide/split the polygon layer at the ...
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1answer
460 views

Knowing the polygon id and getting the extent [duplicate]

I have a text box where I have the polygon Id like, "id_of_the_polygon_12345". Is it possible to get its extent and zoom onto it? I have figured out how to do it upon clicking on the map. But could ...
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2answers
1k views

How to scale/reduce my polygon without changing the central lat & long?

I am writing a VBA code to resize my polygon, I get a input as vector points(Shape file). The code below resizes it as according to my scale factor but my central latitude and longitude are also ...
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2answers
146 views

Zooming into a particular polygon

I am getting the polygon id by doing identifyParams.geometry = evt.mapPoint; identifyParams.mapExtent = map.extent; identifyTask.execute(identifyParams, function(result) { var i; var ...